Light Detection And Ranging (LIDAR) systems are used for object detection and ranging, e.g., for vehicles such as cars, trucks, boats, etc. LIDAR systems also have uses in mobile applications (e.g., for face recognition), home entertainment (e.g., to capture gesture capture for video game input), and augmented reality. A LIDAR system measures the distance to an object by irradiating a landscape with pulses from a laser, and then measuring the time for photons to travel to an object and return after reflection, as measured by a receiver of the LIDAR system. A detected signal is analyzed to detect the presence of reflected signal pulses among background light. A distance to an object can be determined based on a time-of-flight from transmission of a pulse to reception of a corresponding reflected pulse.
It can be difficult to provide robust distance accuracy down to a few cm in all conditions, particularly at an economical cost for the LIDAR system. Promising new, detector technologies, like single photon avalanche diodes (SPADs), are attractive but have significant drawbacks when used to measure time of flight and other signal characteristics, particularly over a broad range of ambient conditions and target distances due to their limited dynamic range.
LIDAR systems would benefit from more accurate methods of detecting reflected laser pulses and measuring their time-of-flight under varying real world conditions. SPAD-based LIDAR systems require new methods to overcome their inherent drawbacks before being a feasible option for economical, long range, accurate 3D imaging. It is also desirable for two or more LIDAR devices to work in close proximity without interfering with each other. It is further desirable for LIDAR systems to operate in an energy efficient manner, without sacrificing accuracy.